Opposition parties use any effort they can to embarrass Obasanjo's government. The polio vaccination program is one.

Safety test rejected

To calm fears, the Nigerian government recently commissioned independent tests to verify the vaccine's safety. At least four series of tests were performed by laboratories in Nigeria and South Africa, all concluding there was no evidence of anti-fertility hormones or the virus that causes AIDS.

In announcing the test results last month, Nigeria's minister of health called on local leaders to join the federal government to drive polio from the country by the end of 2004.

It's unclear whether any of these pronouncements will make a difference. Even before the government declaration, Ahmed announced that the vaccine tests had found evidence of anti-fertility hormones. Anyone who said differently was part of a U.S.-orchestrated cover-up.

The WHO meanwhile pushed ahead with immunization campaigns in the areas of Nigeria that would allow them. The northern states of Kano, Kaduna and Zamfara, with some of the highest infection rates, did not participate.

Distrustful neighbors

In Plateau state, home to a mix of Christians and Muslims, young men and women carrying coolers containing hundreds of doses of the vaccine trudged in blistering heat to hundreds of villages and cities.

They met thousands of families willing to accept the vaccine. But there were pockets of fierce resistance, as the vaccinators discovered in the city of Wase.

A poor farming community, Wase appears almost feudal. At the highest point in the city sits the emir's whitewashed palace. Across the street, just a few feet higher is the mosque, its dome rising over the banks of the Wase River, where peasants tend rows of maize and yams.

The polio vaccine has been available in the village for a decade or more. But opposition to the vaccine has grown steadily since residents heard about the concern in the northern states.

After two years without a case of polio, Plateau state has two children paralyzed by the virus, including one just outside Wase.

Although two cases may seem to be a small number, the risks of infection are high for residents living nearby. For every polio case resulting in paralysis, an estimated 200 people carry the virus but may show no symptoms other than diarrhea.

Such risks, however, were apparently not the primary concern for residents of one neighborhood on the outskirts of Wase. When the team of health workers started knocking on doors, villagers turned them away.

The vaccinators retreated, but then sought help from Wase's traditional ward leader, who is sympathetic to immunization efforts.

"I remember when Americans brought some medicine here once and people got cured," said Albhi Sule Rabo, whose family has ruled over Wase for more than 200 years. "Because I saw this I believe in the vaccine."

Rabo agreed to accompany the vaccinators to the troublesome neighborhood. When his car came within sight, the streets suddenly emptied.

Clearly annoyed, Rabo sprang from his car, barking for the fathers to come outside with their children. He launched into a 10-minute lecture on the benefits of the vaccine and how he had ordered all of his own children to take it. He said there was no reason to believe it was not safe. "God creates medicines," he says.

"Look at this woman," he said, pointing to one of the vaccinators. "She left her husband and children to help us. Do you think she would leave them to come and harm us. Do you think that is believable?"

He focused much of his outrage on one father, a feeble-looking man who stood with his head hung low like a mischievous schoolboy caught by the principal.

"I had heard on the radio that it was dangerous," the man told the vaccination team. After Rabo's speech, he reluctantly agreed to have his child immunized.

The vaccinators pulled a vial of orange-colored liquid from the cooler box, attached a dropper to the top and called over the boy, who squirmed and wailed in his father's arms. His father and two health workers struggled to pry open his mouth.

Then two drops of the vaccine fell to his tongue. His thumb was painted with a dab of purple ink to indicate he had been immunized. The ordeal over, the boy's sobbing suddenly quieted, and his eyes darted back and forth as if to say, "Is that all?"

His work apparently done, Rabo waved goodbye, stepped into his car and drove home.

Their success, however, was short-lived. As soon as Rabo's car disappeared from view, the crowd that had gathered disappeared. The team gave doses to two other children before it encountered a fresh wave of resistance.

One man claimed the vaccine was responsible for the deaths of two of his children. An elderly grandfather sat under a tree and refused to give the whereabouts of his young grandson, who was hiding. A crowd of teen-age boys taunted a group of young women vaccinators.

"What are you going to do? Force us to accept it?" one boy said, laughing.

At the edge of the village the vaccinators approached a man sitting alone under a baobab tree. Alarmed at the sight of them, he stood, waving his arms as if he were trying to stop traffic, saying that he was not about to allow his children to take the vaccine.

"I don't want anything to do with Christians or Americans," he screamed.

Seeing a white American in the party of vaccinators, the man spread his arms as if being crucified and hollered: "Now the Americans have come to kill me. So kill me now!"